1. Field of the Invention
The present invention relates to an ISG control method for a vehicle, and particularly, to an ISG control method under a situation that a vehicle repeatedly stops in a congested area, when an ISG function is implemented in a vehicle with an automatic transmission.
2. Description of Related Art
ISG (Idle Stop & Go) systems improve fuel efficiency of vehicles by stopping the engine in idling, on the basis of information, such as the speed, the rotational speed of the engine, and the temperature of the cooling water when a vehicle stops.
It is also possible to improve fuel efficiency, as described above, by implementing the ISG function in a vehicle with an automatic transmission.
However, a specific control method for a vehicle traveling in a congested area is not provided when implementing the ISG function in the vehicle, which is equipped with an automatic transmission.
That is, as shown in FIG. 1, when the shift lever is at the D-stage or N-stage, the brake is operated (S500), and the maximum traveling speed is at a predetermined level or more, it is determined that the vehicle has traveled after the previous idle-stop (S501), and when the present vehicle speed is at a level where it can be recognized that the vehicle is almost stopped (S502) and other ISG enter conditions are satisfied (S503), the engine is stopped and an idle-stop state is implemented (S504) on the basis of those facts.
Further, when it is requested to restart the engine after the idle-stop state is implemented (S505), the idle-stop state is removed by restarting the engine (S506).
The ISG function is controlled while making a loop entering the idle-stop state and coming out from the idle-stop.
In general, when the control is performed in a congested area, creep traveling for adjusting the inter-vehicle distance right after the engine is stopped is frequently performed, such that the conditions for the history of the maximum traveling speed cannot be satisfied.
Therefore, it is difficult to enter the idle-stop state even if it is required to enter the idle-stop state.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.